Is Matsuzaka Tipping His Pitches?

Check out the video and stills in this SoSH thread.

Most of the times when he's throwing a fastball, Matsuzaka pulls the baseball out near the tip of his glove in his windup. When he's throwing breaking pitches, he keeps the ball buried deeper in his glove. In the examples provided, it seems blindingly obvious, though some posters rightly wonder what the batter is actually seeing from his perspective.

This could be why Matsuzaka is far more effective when pitching with men on base, i.e., not from a full windup.

Batters vs Dice in 2009

                 PA   AVG   OBP   SLG    OPS
  
With Men On     146  .254  .345  .389   .734
With No One On  137  .398  .460  .683  1.143